Ventricular Thrombi and Risk of Embolism after Cardioversion

Although many patients with left ventricular aneurysms have associated mural thrombi, the reported risk of clinical cerebral embolism as a result of cardioversion during electrophysiologic study is remarkably ow' The embohic risk of cardioversion in patients with intraventricular mural thrombi has not been studied systematically, but it is known that protruding and mobile left ventricular thrombi have been reported to be associated with a high risk of emb()hism.24 We report a patient with multiple, "high-risk" mural thrombi who received multiple cardioversions during serial electrophysiologic studies without clinical signs of embelization. A 62-year-old white man suffered an acute anterior myocardial infarction for which he was initially treated with intravenous streptokinase, followed by heparin. Coumadin was subsequently added and heparin therapy discontinued. An echocardiogram on the seventh day post-infarction demonstrated no intraventricular thrombi. Angiography revealed single-vessel disease with total occlusion of the left anterior descending artery after the first septal perforator. An antero-apical aneurysm was noted without evidence ofleft ventricular thrombi. Three weeks after infarction, the patient underwent two serial electrophysiologic studies, during which he required five cardioversions to terminate ventricular tachycardia without embolic complications. An echocardiogram performed four weeks post-infarction revealed the presence of several protruding left ventricular thrombi of up to 2 cm in diameter; at least two were